Firing pin



5.. 17, 1950 R. A. WYKOFF, JR

FIRING PIN Filed Oct. 1 1946 mvN v. I I a i 1 Patented Jan. 17, 1950 vUNITED sures Granted under the act. March- 3'). 1883; as

amended; Apnili 311;; 19283 351]: Q.- GB 7557');

The invention described herein may be manu factured and used by orfort-he- Gbvernmenitfor governmentalpurposes; without the" payment tomepFaIIyrOyaItythereon:

The invention relates to firing pins for r us }in*. gun actions havingreciprocating breeclr closing "boltsand a firing pinreciprocably mountedi'nr the bolt. It is particularly useful in thel3rown ingmachine gun asnow used in the U S; Hriny, illustrations of which may be found thepatents to Browning; 15,298,022; 1 ',628' 2}26; and others:

In these guns great difiiculty has been BEE- perienced because of thebreakage of firing pin p0ints-,=- and it has been a practiceto carry a;number of spare parts including one or: more. spare firing pins; thefiring pins being; quichly attached to a pin= extension which is;mounted i'n the bolt" and is itself detachable from; fireball;

These. guns are embodied in: readily: portable form toa large extent,-and incidentto field service, particularly in jungle warfare is diesirable to reduce impedimenta, because spare parts: have become lostand} failuresoi? firing? pins? have resulted inmany instances-in:putting guns; outof actionpermanently because at lack; oi? aireplacementfiring pini It is therefore an; imiportant aim of this invention: tominimize. the: need for carrying spare firing pins; enabling.- the:production of a reversable' firing.- pinlwhiclr mast be readilyinstalled in a firing. pin: extension as. proximately in: the same, wayas. in. the; present? firing: pim extension; excepting: that a; slight;-en largement ofi the latter isinvolved;

Elias-heretofore been recognized as desirable tmutilizeareversiblefiring pin, but retainingg'the advantages of quick removal: and: reemems and maintenance of the correct. tolerances and; weights in thepartsiha-ve presented a. which was; not overcome. It..-is:thereioreBm'tant aim of thepresent invention to present tepinr which correspondsvery closely tothepim in current use and: whichmay belquickly removed;and reversed or replacedby men in. the. field, principally by manualoperations.

A. further aim is to present'a firing pin assemfilg which. will preservethe rugged characteristics necessary" in a gun action which is subjectedtothe severe use and some abuse in the field.

It alsoan aim to minimize the number of parts required" and topreservethesimplicity of machiningand manual assembl y and replacermerit?operations" involved the improved devicea accompanying drawings;wherein-:

Figure 1 is a longitudinat sectional View of? the bolt and a portion ofthe barrel extension of? a' current modelof Browning machine gun of.50ca-I; as used in the'U-i S.- Army;

179 Figure 2" a" fragmentary top View of the firing pirr extension and"a' part of thefiring pin: bordy engagedtherein; 1

Figure 3 a front end elevation of" the firing pirr extension;-

12s Figure is a sectionof the firingpin and firing' pin extension, onthe line 44* ofiFi'gure 1 Figure 5'' is a; fragmentary-* top view ofmiddle partsof'thefiring pinbody'; Figured; is an endview' of a firingpin hodt 2m in position for insertion in the firing piirexten Figure?is'a fragmentary vertical longitudinal sectional View of"the-*forwardpart of a firing pimextensiom modified; and a: modification of thefiring? pin body? for use therewitli' Figure-8 is a similar viewshowing-means for holding the-rfiring-*- pin body against IOtafiOH irrtheifiringspiirextension;'

Figure: 9115 a View of" the firing pinbod y from Referring moreparticularly to the drawings; there illustrated approximately f-ullsize;that lioit N1 of" the Browning g-un mentioned; in bat relation to thebarrel M, the latter-'- being fixedih the barrel; extension I2 asheretofore,

and aifithis battery position of the parts;- abolt lock- W (:Fi'gure- 1locks: the bolt to the barrel? extensions A sear- I is shown mounted asusual at*- rear end of the" bolt, and a coeking-1everat I5 also;-haiving the usual structureand functiom with the firing pin extension;the rearpart-oft is i entical" with the prior-device excepting:

V foraaslight increasein diameter: 1

The:- foregoing named parts of the structure 45% are well understood andtheir functionsremain unchanged, in consequence ofwhiehthey 'wiil not bedescribed in greater detail pin assembly-in the present instancevcomprises atubular firing pin extension lawman 505 isi practically:identical; in ihrm to the pIiOFIE- pfacedi element" with theexeeption oithe formai oi: thesfonwardi end: thereof; extensiom engaged in alongitudinal main bore l l the halt-g, somewhat; larger in diameterthanthe bore fisr the: prior fi'ring pin ext'ensiong the result" ing thatthe increased weight in my improved device is compensated for by removalof material in the bolt as far as mass in the bolt is concerned. Thefiring pin extension has at the rear the usual vertical longitudinaldiametrical slot 18 receiving therein a slidable sear stop pin I9 bywhich the pin extension is held against roa tation in the bolt. This pinalso serves as a seat for the firing pin spring 26, which is somewhatlarger in diameter than the prior spring, the firing pin extension beingcorrectly bored to permit free action of this spring therein. The larger4 the collar 25. A semicircular retaining flange 39 is thus formed inthe firing pin extension forwardly of channel 35.

A leaf spring 31 is set in a longitudinal slot 38 formed through thewall of the pin extension, the spring being shaped so as to pressdownwardly and engage upon the flat .28 of collar 25 when properlypositioned in the firing pin extension as will be obvious frominspection of Figure 1. The forward extremity of the spring 31 is bentradially outwardly to permit one of the collars 25 to cam lit ioutwardlywhen the firing pin is pressed longispring has an interior diameterwhich is adapted J to receive freely therein a rearwardly directedfiring pin of the same diameter as the prior firing pin, as will bedescribed. Contrary to prior practice, instead of a single seat pinheretofore set across the forward end of the firing pin extentudinallyinto the pin extension with the part 26 uppermost.

. By the formation of the parts as described, it will be seen thatassembly of the pin 22 with extension l6 may be effected by slidingmovement .of pin 22 into the forward end of the firing pin sion as aseat for the forward end of the spring,

two pins 2| are set across the firing pin exten-- sion a distance shortof its forward end, the pins being spaced apart a distance-slightl morethan the diameter of the principal shank portion of the conventionalfiring pin. The firings-pin extension in this instance is also slightlylonger.

than the prior displaced element.

A firing pin body 22 is shown (Figures 1, 4, 5 and 6), having identicalend portions 29 joined by a somewhat thickened middle shank 23 centrallyof which a circular stop flange 24 is formed integrally thereoncorresponding to a similar flange heretofore used on the conventionalfiring. pin and of a diameter slightly less than the diameter of themain bore [1. The forward end of the extension l6 and the two main facesof the flange 24 are planiform and normal to the axis of the bore l1.Spaced from the flange 24 there are integrally formed on the middleshank 23 collars 25 each comprising a semicircular part 26 of relativelylarge diameter and a second semicircular part 21 of less diameter thanpart 26. Flats 28 are formed on parts 21, as clearly shown at Figures 5and 6. End portions 29 which may be circular in cross section orsubstantially rectangular as has been a more recent practice extend fromcollars 25. Each end portion 29 has at its outer part a reducedcylindrical shank 3|) and cylindrical firing pin point 3| ofconventional size and form for engagement through the pressure plate 32at the forward end of the bolt. Points 38 project beyond plate 32 whenthe firing pin assembly is at the forward limit of its movementin thebolt. The bolt has a reduced forward bore 33 adapted to receive thefiring pin proper slidably therein, this bore being enlarged around thepart 30 of the firing pin and reduced adjacent the faceof the bolt tofit snugly around the firing pin point 3i as heretofore, Limitation ofmovement of the firing pin is effected as heretofore byextending bore l1forwardly so that when the firing pin assembly is engaged in the boreand the sear depressed, the forward collar 25 will engage the forwardend of the bore and limit the forward motion of the pin with its pointprojected into the T-slot 34 of the bolt.

Av circular channel 35 is cut in the interior of pin extension [6 adistance rearwardly from its forward end l6 a distance equal to thespacing between the flange 24 and one of the collars-25. Forwardly ofthis channel, the upper half of the pinextension I6 is cut away to anequal radius to form a semicircular entrance channel 36 flush with thebottom of the channel 35, the radius of the channels 35 and 36 isslightly reater than the radius of the semicircular lower part 26 ofextension, the spring 31 being cammed outwardly by portion 26, Figure 6.When the rearward collar 25 has entered sufficiently to align with thechannel 35, the firing pin body is then "rotated 180 so as to bring thesemicircularpart 26 into the channel part 35 behind flange 39 so thatflat 28 is engaged by spring 31. Accidental rotation of the firing pin22 from proper locked position relatively to extension I6 and its escapefrom the firing pin extension are thereby prevented.

If desired, a bevel 26' may be formed as clearly shown at Figure 6, tofacilitate passage of thecollar past the tongue of the spring 31.

The firing pin assembly comprising body 22 and extension I6, may then beintroduced into the bolt in conventional manner and the sear stop pincocking lever and other parts replaced as heretofore.

It is apparent that either end of the firing pin body may be extendedforwardly from the firing pin extension without changing the functionof; the pin and that a quick manual removal and manual replacement ofthe firing pin body in the firing pin extension is made possible with aminimum of effort.

.In Figure '7 there is illustrated a modification: of the invention inwhich the forward part of thefiring pin extension I6 is a simple tubularpart;

with a flush planiform forward end, its bore being slightly enlarged andinteriorly threaded. The

firing pin body in this case has identical end portions as before, butin place of each collar 25, an;

exteriorly threaded concentric boss 40 is integrally formed at the baseof each firing pin proper 29. Between and joining the bosses 40, theflange 24' is formed, corresponding to the flange 24, and

the length of the firing pin body from the flange.

24 to the extremity of each point portion should be approximately thesame as the distance.be.-

tween flange 24 and point 3| in the first described.

The main bore 11' in the bolt in this in-- device. stance is somewhatshorter than the bore I1, and

is counterbored forwardly as at 4| to accommo-' date with clearance theforwardly located boss 40 of the device, and the shoulder 42 thusprovided should engage the flange 24 when the firing pin has its pointin firing position as in Figure 1.

within the bore in extension [6' when'body 22 is unscrewed from theextension and thus prevent the possibility of its loss.

In Figures 8 and 9 the construction is the same as in Figure 7, but theflange 24a corresponding to the flange 24 is peripherally notched as at42' so that the firing pin may be readily rotated by a tool engaged inone or more of the notches, and on the end of the firing pin extensionspring pressed means is provided, arranged to engage in one or more ofthe notches as the firing pin is screwed into place, and so yieldinglhold the firing pin against rotation in the firing pin extension. In thepresent instance the spring device comprises a simple bullet latch 43,although other equivalent devices suitable for the purpose may besubstituted as discretion may dictate.

While I have disclosed the invention with particularity in its best formknown to me, it will nevertheless be understood that this is purelyexemplary and that changes in construction, substitution of materialsand equivalents, mechanical or otherwise, may be made without departingfrom the spirit of the invention set forth in the appended claims.

I claim:

1. An elongated firing pin terminating at one end in a firing pin point,said =pin having, remote from said point, a radial flange comprising twocoplanar semi-circular portions of difierent radii.

2. An elongated firing pin of uniform cross-section tapering to a pointat one end, said pin having first and second axially spaced flangesremote from said point, said first flange comprising two coplanarsemi-circular portions of different radii, said second flange beingcircular and of a radius greater than said first two radii.

3. A firing pin as recited in claim 2, said first flange having itssemi-circular portion of smaller radius bounded by a chord at rightangles to the center radius of said portion.

4. In a firing pin assembly, a tubular firing pin extension having aninternal peripheral channel spaced a predetermined distance from one endthereof, the flange thus formed between said channel and said one endbeing removed throughout of arc, a firing pin tapering to a point at oneend and having a first radial flange remote from said one end, saidflange comprising two semi-circular portions of difierent radii, onesaid portion having a radius equal to the internal radius of saidextension, the other said portion having a radius equal to that of saidchannel, whereby said extension and pin may be united by axiallinserting said pin into the channeled end of said extension, followed bya 180 relative rotation of said pin and extension from a first to asecond position.

5. An assembly as recited in claim 4, said firing pin having a point ateach end, said radial flange being midway between said ends, wherebywhen said pin and extension are assembled, one half of said pin ishoused within said assembly.

6. An assembly as recited in claim 4, said pin having a second radialflange spaced axially from said first flange and constructed andarranged to abut the adjacent end of said extension when said pin andextension are assembled.

7. An assembly as recited in claim 4, said semicircular flange portionof smaller radius being truncated along a chord thereof and spring meanscarried by said extension and adapted to engage said truncated portionto yieldingly maintain said pin in said second position of rotationaladjustment relatively to said extension.

ROY A. WYKOFF, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,284,478 Shepard Nov. 12, 19181,313,912 Reising Aug. 26, 1919 1,696,537 Kewish Dec. 25, 1928 1,993,887Kewish Mar. 12, 1935 2,069,887 Laudensack Feb. 9, 1937

